The problems encountered by past makers of welding devices of the type similar to that of the instant invention are two-fold. The first is with regard to the precision welding gun, and the second is with regard to the capacitive discharge welding base unit.
Regarding the precision welding gun, an example of prior art welding guns is the electroholder gun described by the Italian Pat. No. 957,321 (Spinnato). In the Spinnato device, a helical spring is provided that forms a central fulcrum of its arms. The tips of said arms elastically engage and act so as to close the tips of the gun. The tips are opened only by exerting a force on the arms. The Spinnato structure does not permit the degree of sensitivity obtained by the device described herein.
Moreover, the Spinnato patent does not disclose the quick disconnect feature of this invention, either for its sterilization, or for its substitution with a gun bearing electrodes capable of satisfying different welding requirements. The gun according to the present invention satisfies this, as well as other requirements, advantageously.
Regarding the welding base unit, as is well known in the prior art, an example of prior art devices is an electric welding machine as that disclosed and illustrated in the Italian Pat. No. 957,322 (Spinnato). Spinnato's machine operates on alternating current, and it thus can be supplied only by network voltage, and is manually adapted each time for operation tailored to specific conditions of each welding task. Prior to operation, the setting or adaptation of the device requires a model experimentation to ensure proper operation of the device in real mode. Such preliminary checks are required because of possible changes in the network voltage supply and because of differences in the thickness of the materials to be welded as it is impossible to adjust the pressure of the welding gun employed with such welding devices in operation.
The welding base unit of the instant invention eliminates the aforementioned inconveniences and difficulties in the prior art. The instant unit is free of any problem given by voltage oscillations, as well as of risks to the operator caused by insulation losses relative to network voltage supply, because it is supplied by a direct current voltage source. Such a voltage source may originate from an accumulator or a storage battery, and is made possible by use of electronic components. Furthermore, the instant invention makes use of electronic memory storage in which respective energy requirements of successive voltage pulses in a welding operation are stored for execution upon operator selection and activation. The voltage potential and energy data specifically relate to welding operations as a function of changes in the characteristics of the materials for welding, and in the thickness and other characteristics relating to welding gun pre-loads. In this manner, exact welding operations tailored to various kinds of welding conditions may be reliably reproduced upon operator selection of predetermined voltage pulse sequences, without the need of model experimentation. It is also possible to display or print out the successive sequence information of the entire welding operation.
The device for welding dental elements in accordance with the present invention is suitable for carrying our welding operations in the mouth with any dentally compatible metal, especially with titanium or titanium alloys, for making bridges through the welding of preformed crowns provided with tabs, such as those disclosed in the Italian Patent Application No. 48426A/84 which are the object of said application, by using an interdental precision electric welding gun such as that disclosed in the Italian Patent Application No. 48425A/84 in the name of the same applicant as that of the present application.